Structural panel intended to form part of a cold box of a separation device

ABSTRACT

Structural panel intended to form part of a cold box of a low-temperature distillation separation device, comprising at least one chamber made from carbon steel or chrome and nickel alloy steel, with a rectangular or non-rectangular, optionally isosceles, trapezoid cross-section, having a roof and/or bottom sloping at an angle of between 45° and 60° relative to the panel and one open face, the open face being positioned on the inner face of the structural panel.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of priority under 35 U.S.C. § 119(a) and (b) to French patent application No. FR 1904118, filed Apr. 17,2019, the entire contents of which are incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates to a structural panel intended to formpart of a cold box of a separation device and a cold box comprising sucha panel.

BACKGROUND OF THE INVENTION

Conventionally, low-temperature or cryogenic-temperature distillationseparation units comprise at least one distillation column arranged inan insulating structure known as a cold box (CB). The cold box is ametal enclosure that generally has a substantially parallelepipedalshape so as to form a predetermined insulation thickness around thecolumn and its pipes. The insulation material used is generally perlite.

A low temperature is a temperature below 0° C., or even below −100° C.

The present invention relates to the inner chambers of a CB, housing atleast one accessory selected from the following group: manual valve,automatic valve, flow meter, valve shutter, sensor or otherinstrumentation means. The accessory generally requires access formaintenance operations but is connected to the pipes of the distillationcolumns and/or heat exchangers of a low-temperature orcryogenic-temperature distillation separation device. The mixtures to beseparated comprise air or air gases for ASUs (double main column orargon column) and also a synthesis gas comprising hydrogen and carbonmonoxide, an ammonia synthesis gas comprising nitrogen and hydrogen, amixture comprising carbon dioxide, oxygen and nitrogen or a mixturecomprising carbon dioxide and hydrogen.

The cold boxes can be stick-built units or package units.

Package Units

In order to limit the assembly costs on the installation site, andespecially to control the manufacturing quality, one of the methodscommonly used is to pre-assemble the column with pipe elements andaccessories in the manufacturer's workshop and insert it into a metalenclosure with a cross-section incorporating the future insulationthicknesses all around the column as described in EP 0 913653 A1. Thisassembly, pre-assembled in a horizontal position, known as a packageunit, is then transported and installed on the final construction site.

The package unit assembly option described above nonetheless has thedrawback of considerably increasing the weight of the enclosure in orderto ensure the mechanical stability thereof during the erection phase formoving the package unit from a horizontal position to a verticalposition. In addition to their weight, which significantly increases thetransport costs, these package units are also faced, largely due totheir considerable volume, with serious problems limiting theirtransport (fitting under or over bridges or through tunnels, aroundbends, under electricity lines, etc.).

SUMMARY OF THE INVENTION

According to certain embodiments of the invention, when the CBs areprefabricated as package(s) (comprising one or more sub-packages), bothin a workshop and directly on the installation site, at least oneaccessory of the CB selected from the following group: manual valve,automatic valve, flow meter, valve shutter, sensor or otherinstrumentation means, etc. requiring its installation in a separatechamber fastened to the inner walls of the CB, is installed in anaccessory chamber, parallelepipedal in shape but with roof and/or bottomfaces sloping at between 45° and 60° to the horizontal in order toprevent the perlite from banking and a loss of performance of theinsulation. The chamber is in turn installed in the package in order tomake it possible to insulate it thermally, generally with rock wool,once installation on the construction site is complete and before thestarting of the CB, which in turn is filled with a powdered insulationmaterial such as perlite. This installation in dedicated chambers,making it possible to be isolated from the perlite, ensures access bymaking it possible to easily remove the rock wool insulation with whichthey are filled, in the event of subsequent operations for inspection ormaintenance for example of the elements or accessories that theycontain.

In this type of design, the assembly and production of the accessorychambers, as it is carried out in a horizontal position in the workshop,does not make the manufacturing of the package units more complex. Theconstraints generated by this design are mainly the additional cost ofthe material of the enclosure and the limited transportability.

Stick-Built Units

For stick-built design, the CBs are entirely assembled on theconstruction site. That is, all of the pipes of the CB must be installedone by one and connected to the vertical distillation column and/or toother columns, to cryogenic exchangers and/or to pumps and/or toturbines at a height ranging from ground level to approximately 60 m.Similarly the accessories (manual or automatic valves, flow meters,valve shutters, miscellaneous sensors, etc.) must be connected to thesepipes one by one, which requires a lot of manpower and a large quantityof scaffolding and does not facilitate worker productivity.

These accessory chambers are also produced on the construction site.These accessory chambers can be located on any inner face of the CB at aheight varying from ground level to approximately 60 m. These chambersare the same type as those installed in the package units and house theaccessories described previously.

In this type of CB assembly, one of the challenges is to significantlyreduce the installation time and planning risks of the CB by limitingthe construction activities as much as possible while guaranteeing alevel of quality comparable to the manufacturing of the package units inthe workshop.

To this end, measures are taken to offer a high level of prefabricationof the carbon steel jacket structures of the CB. This involves theprefabrication in panel form of the various structural elements of theCB. These various panels can be rectangular and flat (flat panels),angled (corner panels) and also in the form of a portion of a sector ofa circle (shell panels), and are described for example inUS20060162379A1.

During the design of a stick-built cold box, the present inventionfirstly proposes designing a chamber housing the various accessories(manual or automatic valves, flow meters, valve shutters, miscellaneoussensors, etc.) and having it manufactured in the manufacturer'sworkshop.

Secondly, for even greater optimization of the on-site constructionphase, the distillation column can be partially provided, in themanufacturer's workshop, with some of its pipes, obviously such as thosethat will have to be connected to the accessory chambers in order tofully restore the pipe network once the accessory chamber fastened toits structural panel has been put in place and after welding of the pipeinterfaces of said chamber with the pipe spools installed in advance onthe distillation column.

This chamber will then be sent, as will the distillation column providedwith some of its pipe spools, to the construction site.

This chamber will have at least one open face that will subsequently bein contact with the structural panel of the CB.

This chamber, the structure of which will preferably be made from carbonor stainless steel, will preferably by provided with handling means,known as lifting lugs, so that it can be handled in order to connect itby welding or bolting to the inner face of a structural panel of theprefabricated CB.

The chamber is preferably connected to the structural panel on theground, at breast height or a height only requiring a small mobilescaffold, before final lifting and positioning of the structural panelaround the distillation column in order to minimize the risks and reduceoperations at height, which are generally very costly.

Pipe spools comprising their associated accessories as describedpreviously will also be installed in this prefabricated chamber.

These pipe spools, in this prefabricated chamber, will have permanent ortemporary supports for securing the pipe spools and accessories duringthe transport and handling phase with a view to connecting the panel,and during the handling of the panel and its final positioning aroundthe distillation column.

The present invention aims to provide assembly means that make itpossible to both maintain the quality criteria relating to the workshoppre-assembly of the elements requiring strict quality control (typicallythe entire cryogenic part), and greatly limit the problems and costsrelating to transport to the construction site and facilitate theinstallation on the construction site of the stick-built cold boxes.

Such a method, which no longer takes into consideration, for itspre-assembly and transport, the volume of insulation necessary for thecolumn or the enclosure that contains the insulation, makes it possibleto increase the options for transporting a sub-assembly of a cryogenicunit such as a distillation column by reducing the overall dimensionswhile allowing a high level of controlled prefabrication in theworkshop.

According to one object of the invention, a structural panel intended toform part of a cold box of a low-temperature distillation separationdevice is provided, comprising at least one chamber made from carbonsteel or stainless steel, for example comprising chrome and nickel, witha rectangular or non-rectangular, optionally isosceles, trapezoidcross-section, having a roof and/or bottom sloping at an angle ofbetween 45° and 60° relative to the panel and one open face, the openface being positioned on the inner face of the structural panel.

According to other optional features:

-   -   the panel contains at least one accessory selected from the        following group: manual valve, automatic valve, flow meter,        valve shutter, sensor or other instrumentation means, as well as        a pipe spool connected to the accessory;    -   the chamber comprises at least one means for handling the        chamber and at least one permanent or temporary support to        support the at least one pipe spool and/or the at least one        accessory during the transport phases and the connection to the        structural panel;    -   the chamber is fastened to the panel by welding or bolting,        preferably on the ground before lifting;    -   the chamber comprises at least one perforated face covered with        a material that is impermeable to a particular insulation        material, for example to perlite, but permeable to a flushing        gas; and/or    -   the chamber contains rock wool and/or aerogel.

According to another aspect of the invention, a cold box of alow-temperature distillation separation device is provided, comprisingat least four vertical walls, at least one of which consists of orcomprises a panel as described above, the cold box being filled withinsulation material and containing at least one element of the deviceintended to operate at a low temperature, or at a cryogenic temperature(e.g., a temperature at or below −50° C.).

The cold box preferably contains at least one distillation column and/orat least one heat exchanger.

According to another object of the invention, a method for assembling acold box of a low-temperature distillation separation device isprovided, comprising at least four panels to be arranged verticallyaround one element intended to operate at a low temperature, or at acryogenic temperature, in which the wall of at least one panel isprovided with a chamber made from carbon steel or chrome and nickelalloy steel, with a rectangular or non-rectangular, optionallyisosceles, trapezoid cross-section, having a roof and/or bottom slopingat an angle of between 45° and 60° relative to the panel and one openface, by fastening the open face to the inner face of the structuralpanel.

The chamber can be fastened to the panel in a workshop or on the coldbox installation and/or construction site.

Preferably, the panels are fastened together once the chamber isfastened to the panel.

BRIEF DESCRIPTION OF THE DRAWINGS

Further features and advantages of the invention will become apparentfrom the description hereinafter of embodiments, which are given by wayof illustration but without any limitation, the description being givenin relation with the following attached figures:

FIG. 1 is a vertical cross-section of a chamber fastened to a panelaccording to the invention.

FIG. 2 is an exploded view of a cold box comprising two panels accordingto the invention.

FIG. 3 illustrates the chamber in more detail.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 illustrates a panel 5 of a cold box of a distillation airseparation device; the cold box can contain a column and/or a heatexchanger. An element 3 to be insulated is illustrated as beingsurrounded with perlite 15. Fastened to the inner face of the panel 5 isa chamber 1 made from carbon steel or chrome and nickel alloy steel(stainless steel). It has a roof at an angle of 60° relative to avertical plane, which is the plane of the panel 5. The bottom is slopedat 45° relative to the panel. Other angles between 45° and 60° arepossible.

This serves to prevent the perlite 15 surrounding it from banking. Thechamber 1 has one open face, the open face being positioned on the innerface of the structural panel 5. Inside the chamber 1 is at least oneaccessory 9 that can be a manual valve, an automatic valve, a flowmeter, a valve shutter or a sensor. The accessory is connected, ifnecessary, to the outside of the cold box through the panel 5 and a boot8 to its actuator 10.

The chamber 1 is filled with rock wool 11.

The chamber has a trapezoid cross-section. In the figure, it is anon-rectangular, non-isosceles trapezium, as the roof is sloped at 60°to the vertical and the bottom is sloped at 45° to the vertical. It isalso possible for the two angles to be identical. Otherwise, the roofand/or the bottom can be perpendicular to the panel, in which case thecross-section is a rectangular trapezium shape.

At least one wall of the chamber 1 can be perforated, for example beingmade from mesh or expanded metal 18. The mesh is covered with a materialimpermeable to a particular insulation material, with which the box isfilled, for example to perlite 15, but permeable to a flushing gas. Theallows the flushing gas, for example nitrogen, which circulates in theperlite 15, to circulate in the chamber in order to prevent theformation of pockets of ice or the build up of other impurities.

In FIG. 2, a distillation column 3 is arranged in a cold box consistingof eight corner panels 5, 5A having an L-shaped cross-section. Only fourof the panels can be seen in the figure. The panels 5, 5A each have achamber 1 fastened to the inner wall. Obviously, the panels of the coldbox do not necessarily hold chambers. Again, the chamber is made fromcarbon steel or chrome and nickel alloy steel (stainless steel). It hasa roof at an angle of 60° relative to a vertical plane, which is theplane of the panel 5. The bottom is sloped at 45° relative to the panel.

The chamber(s) contain(s) rock wool and the cold box is filled withperlite in use.

The column 3 is provided with pipes and can be connected to an accessorypresent in one of the chambers.

The chambers 1 can be fastened to the panels 5, 5A by welding orbolting. It is preferable to fasten the chamber to the panel 5A on theground and then lift the panel 5A into position above the panel 5. It ishowever possible to position the chamber subsequently on its structuralpanel after said panel has been lifted, through an opening in the roofof the CB, or to slide it from the outside through one face of astructural panel using the catwalks of the CB.

FIG. 2 shows that the chambers are positioned before the panels of thecold box are attached to each other.

FIG. 3 shows details of the chamber 1 with its accessories such as amanual valve, automatic valve, flow meter, valve shutter or sensor,together with a pipe spool 23 connected to the accessory. The actuator10 of the valve 9 extending outside, and the wire 21 enabling thesubsequent connection of the instrumentation, can also be seen.

While the invention has been described in conjunction with specificembodiments thereof, it is evident that many alternatives,modifications, and variations will be apparent to those skilled in theart in light of the foregoing description. Accordingly, it is intendedto embrace all such alternatives, modifications, and variations as fallwithin the spirit and broad scope of the appended claims. The presentinvention may suitably comprise, consist or consist essentially of theelements disclosed and may be practiced in the absence of an element notdisclosed. Furthermore, if there is language referring to order, such asfirst and second, it should be understood in an exemplary sense and notin a limiting sense. For example, it can be recognized by those skilledin the art that certain steps can be combined into a single step.

The singular forms “a”, “an” and “the” include plural referents, unlessthe context clearly dictates otherwise.

“Comprising” in a claim is an open transitional term which means thesubsequently identified claim elements are a nonexclusive listing (i.e.,anything else may be additionally included and remain within the scopeof “comprising”). “Comprising” as used herein may be replaced by themore limited transitional terms “consisting essentially of” and“consisting of” unless otherwise indicated herein.

“Providing” in a claim is defined to mean furnishing, supplying, makingavailable, or preparing something. The step may be performed by anyactor in the absence of express language in the claim to the contrary.

Optional or optionally means that the subsequently described event orcircumstances may or may not occur. The description includes instanceswhere the event or circumstance occurs and instances where it does notoccur.

Ranges may be expressed herein as from about one particular value,and/or to about another particular value. When such a range isexpressed, it is to be understood that another embodiment is from theone particular value and/or to the other particular value, along withall combinations within said range.

All references identified herein are each hereby incorporated byreference into this application in their entireties, as well as for thespecific information for which each is cited.

1. A structural panel configured to form part of a cold box of a low-temperature distillation separation device, comprising at least one chamber made from carbon steel or stainless steel, the panel having a cross-section, having a roof and/or bottom sloping at an angle of between 45° and 60° relative to the panel and one open face, the open face being positioned on the inner face of the structural panel.
 2. The panel according to claim 1, containing at least one accessory selected from the group consisting of a manual valve, an automatic valve, a flow meter, a valve shutter or other instrumentation means, a pipe spool connected to the accessory, and combinations thereof.
 3. The panel according to claim 1, in which the chamber comprises at least one means for handling the chamber and at least one permanent or temporary support to support the at least one pipe spool and/or the at least one accessory during the transport phases and the connection to the structural panel.
 4. The panel according to claim 1, in which the chamber is fastened to the panel by welding or bolting, preferably on the ground before lifting.
 5. The panel according to claim 1, in which the chamber comprises at least one perforated face covered with a material that is impermeable to a particular insulation material, for example to perlite, but permeable to a flushing gas.
 6. The panel according to claim 1, in which the chamber contains rock wool and/or aerogel.
 7. The panel according to claim 1, wherein the cross-section is selected from the group consisting of rectangular, non-rectangular, isosceles, and trapezoidal.
 8. A cold box of a low-temperature distillation separation device, comprising at least four vertical walls, at least one of which comprises the panel according to claim 1, the cold box being filled with an insulation material and containing at least one element of the device configured to operate at a low temperature or at a cryogenic temperature.
 9. The cold box according to claim 8, further comprising at least one distillation column and/or at least one heat exchanger.
 10. A method for assembling a cold box of a low-temperature distillation separation device, comprising at least four panels to be arranged vertically around one element configured to operate at a low temperature or at a cryogenic temperature, wherein the wall of at least one panel is provided with a chamber made from carbon steel or chrome and nickel alloy steel, having a roof and/or bottom sloping at an angle of between 45° and 60° relative to the panel and one open face, by fastening the open face to the inner face of the panel.
 11. The method according to claim 9, wherein the chamber is fastened to the panel in a workshop.
 12. The method according to claim 9, wherein the chamber is fastened to the panel on the installation site of the cold box.
 13. The method according to claim 9, wherein the chamber is fastened to the panel on the construction site of the cold box.
 14. The method according to claim 9, wherein the panels are fastened together once the chamber is fastened to the panel.
 15. The method according to claim 9, wherein the cross-section is selected from the group consisting of rectangular, non-rectangular, isosceles, and trapezoidal. 